Comparison of enzyme activities linked to acid-base regulation in a deep-sea and a sublittoral decapod crab species

Eric F. Pane, Martin Grosell, James P. Barry

Research output: Contribution to journalArticlepeer-review

5 Scopus citations

Abstract

When compared to the sublittoral Dungeness crab Cancer magister, the deep-sea Tanner crab Chionoecetes tanneri exhibited lower activities of enzymes involved in some of the processes essential for efficient acid-base regulation. Tissue enzymatic activities were compared between Dungeness crabs held in normoxia and Tanner crabs held in hypoxia-both treatments mimicking typical habitat oxygen levels. In the posterior gill, activities of all forms of ATPase and carbonic anhydrase (CA) were approximately 2- to 13.2-fold lower in Tanner crabs than in Dungeness crabs. CA activity in the heart and white muscle was also significantly lower in hypoxic deep-sea Tanner crabs, while ATPase activity in these 2 tissues was similar between the 2 treatments. Diagnostically, enzymatic activities were compared when both species were held in normoxic seawater, with additional significant differences found in specific white muscle ATPase fractions (amiloride- and N-ethylemaleimide [NEM]-sensitive ATPases) and tissue buffering (β) capacity. When both species were acclimated to normoxia, C. tanneri exhibited mass specific rates of oxygen consumption significantly lower (4.5-fold) than C. magister. Under short-term, strongly hypercapnic conditions (1% CO2), the Dungeness crab displayed reduced (30 to 40%) branchial ATPase activities, while enzymatic activities in the Tanner crab gill, muscle and heart were refractive to short-term (24 h) hypercapnia, suggesting a minimal ability to tune branchial function to changing environmental conditions. These results support our hypothesis that the deep-sea Tanner crab has a reduced capacity for active transport of acid-base relevant ions, particularly at the gill, and is therefore at a marked disadvantage with respect to iono-and acid-base regulatory capacity. These results add to a growing database documenting the limited ability of deep-sea megafauna to compensate for internal acid-base disruptions associated with introduction of anthropogenic CO2 into the deep sea.

Original languageEnglish (US)
Pages (from-to)23-32
Number of pages10
JournalAquatic Biology
Volume4
Issue number1
DOIs
StatePublished - Dec 1 2008

Keywords

  • Acid-base regulation
  • CO
  • Decapod crustacean
  • Deep sea
  • Physiology

ASJC Scopus subject areas

  • Aquatic Science
  • Oceanography
  • Ecology, Evolution, Behavior and Systematics
  • Ecology

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